GS750E Caliper upgrade

[WillKo]

I have a 1978 GS750E Resto Mod and I am looking to put TL1000 front calipers on it, has anyone done that before?

[Nessism]

The problem with modern calipers on GS bikes, is the calipers hit the wheel. GS member Salty_Monk has done all the legwork towards installing dual piston calipers on your bike, you might want to check out his thread.

[WillKo]

Thanks, I'll get in touch with him.

[salty_monk]

Yeah the stock GS forks aren't wide enough to allow an opposed piston caliper.

You'd have to basically change out the whole front end.

Linky to the main thread below in my signature but there are other threads including one more for the single brake models.

[Suzukian]

Sometimes, a newer wheel may do the trick. I have 3 spoke early Katana wheels ready (they will need new bearings to accommodate the 1150 axle) for my '83 GS750ES, and a GS1150 front end, progressive springs, Tokico calipers happen to fit, but I had to get different discs. It's a project not for those faint of heart. I want cartridge emulators. Those will be the last thing I do if I feel I need them. I am satisfied with the anti-dive.

[dorkburger]

Sometimes, a newer wheel may do the trick. I have 3 spoke early Katana wheels ready (they will need new bearings to accommodate the 1150 axle) for my '83 GS750ES, and a GS1150 front end, progressive springs, Tokico calipers happen to fit, but I had to get different discs. It's a project not for those faint of heart. I want cartridge emulators. Those will be the last thing I do if I feel I need them. I am satisfied with the anti-dive.

I bought a used set of 1150 forks with Sonic straight rate springs and emulators installed from a member here. I gutted the “non serviceable” PDF units to render them as non functional. It’s a nice improvement

[Suzukian]

Not sure what "PDF" units means, is that the "Anti-Dive", pardon my ignorance? I have found the "Anti-Dive to be extremely useful, especially on the windy twisty New England roads. I have found when people complain about them, they usually aren't working right. I have taken a few apart to see rusty components, which means somehow water go in there.

Mine has been working mine since I purchased the bike. I would like to try and make a set of cartridge emulators, but I think the 1150 front end on the GS750 ES with progressive spring kit I have to install will make the front end even less prone to diving.

[dorkburger]

The PDF on the 1150 was the replacement for the brake fluid activated anti dives on the older bikes.

[Suzukian]

dorkburger I know what you refer top now, the PDF (Positive Damping Force) which was isolated and different before the pre '84 models. Personally, and it may be my riding styles, and familiarity with the roads I decide to rip up, I really like the anti-dive units.

I have drive friends, and have had them follow me on these unique New England roads, which would be road race worth, some get you 3 feet into the air easily, and a few almost drove off into the stone walls, grabbing handfuls of brake, losing their rear tire grip. When they then road my Suzuki, they really appreciated the "Anti-Dive' units.

From what Salty Monk has told me is that fork emulators are doing close to the same thing. I have the machines to produce these things, but the problem I see is that you can't adjust them without taking the bike apart. It would see that once you have the proper plates, a long bolt, with a polished shank, with )-Ring grove,, could take "O-Rings', and allow for adjustment of the spring through the top of the fork legs (respectively). I would need a good set of Blueprints, and see how they are physically mounted, to produce these things. They seem simple enough to make.

It really interests me. If I could get these down, I wouldn't mind making them for people who I would just need to cover the expense.

Thanks for the explanation. I really appreciate it.

.................(Please forgive my spelling, I have fat finger syndrome)

[salty_monk]

It's not difficult just a bit messy as you have to support the front end, take the caps off & pull the spring and spacers to get to it. Probably a 20 min job if you're rushing...

[Suzukian]

With my bad neck and back, I stopping rushing 30 years ago!! I do think an adjuster rod, with proper sealing, through custom made caps (the host the seals), could make adjustable springs, with minimal weight added.

[WillKo]

Since I'm new to this forum I might not be using it properly, I'm not finding consice information on the rotors used in the conversion. From what I gather CBR900RR, CBR900R, CBR600F3 will all work, what about SV600 rotors? If I have it wrong please clarify for me, I plan on ordering the rotors and I want to make sure what I get will work.

[salty_monk]

Since I'm new to this forum I might not be using it properly, I'm not finding consice information on the rotors used in the conversion. From what I gather CBR900RR, CBR900R, CBR600F3 will all work, what about SV600 rotors? If I have it wrong please clarify for me, I plan on ordering the rotors and I want to make sure what I get will work.

No SV650 will not work. CBR600F3 from 96-99 definitely work but need a new bolt circle drilled and an offset spacer. SOME but not all of the CBR900 and F4 rotors work. All need the holes enlarging and an offset spacer.
I can usually identify the OEM one visually from a picture (But even then there are some 900R or RR ones that are the wrong diameter at the braking surface even though the spider is correct)

[salty_monk]

With my bad neck and back, I stopping rushing 30 years ago!! I do think an adjuster rod, with proper sealing, through custom made caps (the host the seals), could make adjustable springs, with minimal weight added.

The problem you'd have is that they are under the springs so your adjuster would have to allow for the travel of the fork

[Suzukian]

The problem you'd have is that they are under the springs so your adjuster would have to allow for the travel of the fork

That would be quite a sight to watch, those adjusters following the road. I was thinking if you made them on a "half round" slider (the end would have to be welded to the adjusting bolt), inside a halve round tube, with a snap ring, they could be adjustable and stay in place, allowing for adjusting on the fly. Up at top there would have to be a round part for a seal. I could do a CAD drawing, but I'm sure you know what I mean, just like I'm sure you think it's not worth it..................... which is what I'm thinking.